i read this manga a crazy long time ago and i seriously can't remember anything about other then the fact that its one of those worker/secretary X Boss/head of company mangas and at one point in order to become more "sensitive" the boss uses a nipple pump....reading this back it sounds extremely weird but if you know what im talking about and could help me i would be internally grateful. 😀

Pump

I also searched and I found.

Zankokuna Kimi to Tomoni

Is this the manga?